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Suitability level: High class.

The G-Class delivers rock-solid off-road performance for the Swiss Army.

Since 2016, the G-Class has been in service with the Swiss Army with a fleet of 3,200 vehicles. As a delivery van, the G 300 CDI model impresses above all with its robustness and off-road capability, among other things. With the help of modern assistance systems, differential locks, rigid axles and the reduction gearbox, the G also manages to negotiate difficult terrain. Two real off-road experts put this to the test at the G-Class Experience Center in Graz (Austria). Marc Sussner, chief instructor of the G-Class, and Roland Sollberger from the Swiss Army's Competence Centre for Driver Training put the G 300 through its paces.

Dynamic on all surfaces.

"At the end of our driver training, it will be much dirtier, more appropriate." Marc Sussner knows the terrain in which the G-Class feels at home. For now, the matt military green car is still presentable and clean. That will change in the course of the vehicle test. The chief instructor of the G-Class is standing on the grounds of the G-Class Experience Center with adjutant NCO Roland Sollberger from the Swiss Army's Centre of Competence for Driver Training. Together they are going to demonstrate what the G-Class can do in the field.

Different surfaces can be simulated on the chassis dynamometer, for example snow and ice. Differential locks are essential to ensure that the vehicle retains its traction, even with spinning tyres. Marc Sussner shows how they work. Just like the new G-Class for rescue and special operations, the G 300 has three differential locks – the longitudinal lock, also called the centre lock, and a lock for each axle. If one or more wheels lose traction and start to spin, the differential locks ensure that the power can still be distributed evenly to the remaining wheels that have traction. In the corresponding test, the G-Class behaved absolutely exemplary.

The G-Class for Rescue and Special Operations.

However, the differential locks should never be engaged on asphalted roads. If you drive into a bend with the differential lock activated, the inner wheels have to cover a shorter distance with the same torque. Consequence: The tyres rub heavily. In the worst case, the differential can even be damaged.

ESP and ABS regulate.

In everyday road traffic, the G-Class is of course equipped with an Electronic Stability Programme (ESP) and an Anti-Lock Braking System (ABS), the "little helpers" on the tarmac. In the G-Class Experience Center, it can demonstrate its driving safety in a slalom and on wet roads.

At moderate speed, the slalom is no problem: not even the control systems have to step in. Only at higher speeds does the ESP system intervene in the bends and briefly apply heavy braking to the wheels on the outside of the bend. The G also masters full braking effortlessly. "Flawless," says Roland Sollberger. In this case, the ABS assists by preventing individual wheels from locking under heavy braking.

When changing lanes on wet roads, things get a little trickier. Even small increases in speed can have a big impact on the handling. Roland Sollberger pushes the G-Class to the limit and drives towards an obstacle at speeds of up to 70 km/h. In addition to the control systems, this requires a lot of experience.

When intervening in control systems, it is generally recommended to drive carefully to avoid pushing the vehicle to its limits. Important: In driving safety tests, controlled dangerous situations are deliberately tested. In everyday life, on the other hand, such situations take you by surprise and can lead to knee-jerk reactions. Even the experienced Roland Sollberger warns: "Never try such things in road traffic."

G will rock you.

Now it's time for the real thing: Marc Sussner and Roland Sollberger climb the infamous G Rock, the centrepiece of the G-Class Experience Center, with the G 300. There, the off-road vehicle can show how well it can handle inclines.

First, it climbs up the gravel road with a gradient of 30 % or 60 %, through bumps and washed-out ground. The G-Class gets stuck – now two of the three differential locks can be tested in action. Does the stoic calm of the G rub off on Roland Sollberger, or vice versa?! Either way, the vehicle gently releases itself from the sinking.

 

Off-road, the rule is: as much throttle as necessary, as little throttle as possible.

Marc Sussner, Chief instructor Mercedes-Benz G-Class

It’s all downhill from there: the G 300 masters the 80 % gradient with the help of the reduction gearbox, which doubles the braking power of the engine brake and better transmits the steering forces of the vehicle. It rolls elegantly downhill. However, the tried and tested engine brake reaches its limits when it comes to uneven descents. On the rocky slope, Roland Sollberger has to apply the brake manually, with a lot of finesse. The sworn team masters this too with flying colours. There is a golden rule for off-road driving, which Marc Sussner advises to keep in mind: "As much throttle as necessary, as little throttle as possible."

 

If you are so inclined.

When driving off-road, driving at an angle can be a challenge. Fortunately, the G-Class is perfectly prepared for it. "Even as chief instructor, I can't tell you the true tipping point of the vehicle," Marc Sussner admits. That depends on many factors, such as speed, roof load and tyre pressure.

As a rule, however, gut feeling and common sense put a stop to overly wobbly driving in good time. Those who prefer to rely on their vehicle should keep an eye on the tyre pressure – the lower side is exposed to a high load and the wheels only have contact with the ground at the outer edge.

When driving on-road, there is usually no slanting outside the test track. The situation is different off-road. That's where the G-Class really feels at home. In the woods of the G-Class Experience Center, it goes all out. To prevent the G-Class from going astray, it is important to stay on the path. There, it keeps perfectly on track, but the steering behaviour is clearly limited. As soon as you are in an inclined position, you should not steer upwards – hardly any steering forces are transmitted there. Instead, it makes sense to always steer into the "fall line", i.e., downwards, and maintain a slow pace.

Ramping up with the G-Class.

Axle articulation is a special challenge for any off-road vehicle. For the G-Class, however, this is no cause for alarm. Because it is capable of keeping all wheels on the ground even on very uneven surfaces. This is made possible by rigid axles, which have a longer suspension travel. But even rigid axles have their limits off-road, despite their advantage over wheels with independent suspension. Marc Sussner and Roland Sollberger explore these limits.

The adjutant NCO is ready. "We can do it together! You, the G and I," assures Marc Sussner. A strong team. Under the directions of the chief instructor, Roland Sollberger carefully drives up the ramp, right up to the tipping point of the car. Until one wheel hangs in the air.

"At this point, you can also simply tip a vehicle over by hand," as Marc Sussner immediately demonstrates.

But the G-Class can also do that on its own. If the vehicle starts to tilt on the ramp, it is important to wait until it stops bouncing to take out energy. "The safest thing is simply to have the vehicle standing still," says Marc Sussner. Then the G 300 can't be put in its place.

Want a mud-bath?

The G-Class makes it out of any muddle. With a fording depth of 600 mm, it is fully capable of driving through water. However, you have to take into account the bow wave, which has to be added to the actual water depth. That means: drive slowly and evenly. You also need two differential locks as a precaution.

In order to stay on top of things, you should always wade through the water beforehand to estimate the depth. When driving through, the windows must also be rolled down a crack so that you can open the doors in an emergency. In the forest, on the other hand, you should always keep the windows closed in case branches protrude into the roadway or the vehicle even tips over.

When driving through mud, the vehicle behaves very much like it does in water. This means selecting two differential locks and preselecting second or third gear to avoid getting stuck in the mud is recommended. The intake snorkel, by the way, is not designed to go diving. It ensures a clean air supply to the engine when driving through sand or other surfaces where particles are stirred up.

Generalist off-road.

With its numerous assistance systems and extensive off-road equipment, the G-Class is a robust vehicle for a wide range of rescue and special operations. No matter which elements it is exposed to. Whether in the forest, in the river or in the desert: the G is an emergency vehicle you can rely on. Marc Sussner and Roland Sollberger end their day at the G-Class Experience Center satisfied and attest to the off-road vehicle's suitability: high class.